/***************************************************************************
    copyright            : (C) 2003 by Ismael Orenstein
    email                : orenstein@kde.org
 ***************************************************************************/

/***************************************************************************
 *   This library is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU Lesser General Public License version   *
 *   2.1 as published by the Free Software Foundation.                     *
 *                                                                         *
 *   This library is distributed in the hope that it will be useful, but   *
 *   WITHOUT ANY WARRANTY; without even the implied warranty of            *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU     *
 *   Lesser General Public License for more details.                       *
 *                                                                         *
 *   You should have received a copy of the GNU Lesser General Public      *
 *   License along with this library; if not, write to the Free Software   *
 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA         *
 *   02110-1301  USA                                                       *
 *                                                                         *
 *   Alternatively, this file is available under the Mozilla Public        *
 *   License Version 1.1.  You may obtain a copy of the License at         *
 *   http://www.mozilla.org/MPL/                                           *
 ***************************************************************************/

#include "tbytevector.h"
#include "tstring.h"
#include "tdebug.h"

#include "xingheader.h"
#include "mpegfile.h"

using namespace Strawberry_TagLib::TagLib;

class MPEG::XingHeader::XingHeaderPrivate {
 public:
  explicit XingHeaderPrivate() : frames(0), size(0), type(MPEG::XingHeader::Invalid) {}

  unsigned int frames;
  unsigned int size;

  MPEG::XingHeader::HeaderType type;
};

////////////////////////////////////////////////////////////////////////////////
// public members
////////////////////////////////////////////////////////////////////////////////

MPEG::XingHeader::XingHeader(const ByteVector &data) : d(new XingHeaderPrivate()) {
  parse(data);
}

MPEG::XingHeader::~XingHeader() {
  delete d;
}

bool MPEG::XingHeader::isValid() const {
  return (d->type != Invalid && d->frames > 0 && d->size > 0);
}

unsigned int MPEG::XingHeader::totalFrames() const {
  return d->frames;
}

unsigned int MPEG::XingHeader::totalSize() const {
  return d->size;
}

MPEG::XingHeader::HeaderType MPEG::XingHeader::type() const {
  return d->type;
}

////////////////////////////////////////////////////////////////////////////////
// private members
////////////////////////////////////////////////////////////////////////////////

void MPEG::XingHeader::parse(const ByteVector &data) {

  // Look for a Xing header.

  size_t offset = data.find("Xing");
  if (offset == ByteVector::npos())
    offset = data.find("Info");

  if (offset != ByteVector::npos()) {

    // Xing header found.

    if (data.size() < static_cast<unsigned long>(offset + 16)) {
      debug("MPEG::XingHeader::parse() -- Xing header found but too short.");
      return;
    }

    if ((data[offset + 7] & 0x03) != 0x03) {
      debug("MPEG::XingHeader::parse() -- Xing header doesn't contain the required information.");
      return;
    }

    d->frames = data.toUInt32BE(offset + 8);
    d->size = data.toUInt32BE(offset + 12);
    d->type = Xing;
  }
  else {

    // Xing header not found. Then look for a VBRI header.

    offset = data.find("VBRI");

    if (offset != ByteVector::npos()) {

      // VBRI header found.

      if (data.size() < static_cast<unsigned long>(offset + 32)) {
        debug("MPEG::XingHeader::parse() -- VBRI header found but too short.");
        return;
      }

      d->frames = data.toUInt32BE(offset + 14);
      d->size = data.toUInt32BE(offset + 10);
      d->type = VBRI;
    }
  }

}
